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This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The mask-position CSS property sets the initial position, relative to the mask position layer set by mask-origin, for each defined mask image.

/* Keyword values */
mask-position: top;
mask-position: bottom;
mask-position: left;
mask-position: right;
mask-position: center;

/* <position> values */
mask-position: 25% 75%;
mask-position: 0px 0px;
mask-position: 10% 8em;

/* Multiple values */
mask-position: top right;
mask-position: 1rem 1rem, center;

/* Global values */
mask-position: inherit;
mask-position: initial;
mask-position: unset;

Initial valuecenter
Applies toall elements; In SVG, it applies to container elements excluding the defs element and all graphics elements
Inheritedno
Percentagesrefer to size of mask painting area minus size of mask layer image (see the text for background-position)
Mediavisual
Computed valueConsists of two keywords representing the origin and two offsets from that origin, each given as an absolute length (if given a <length>), otherwise as a percentage.
Animation typerepeatable list of simple list of length, percentage, or calc
Canonical orderper grammar

Syntax

One or more <position> values, separated by commas.

Values

<position>
One to four values representing a 2D position regarding the edges of the element's box. Relative or absolute offsets can be given. Note that the position can be set outside of the element's box.

Formal syntax

<position>#

where
<position> = [ [ left | center | right ] || [ top | center | bottom ] | [ left | center | right | <length-percentage> ] [ top | center | bottom | <length-percentage> ]? | [ [ left | right ] <length-percentage> ] && [ [ top | bottom ] <length-percentage> ] ]

where
<length-percentage> = <length> | <percentage>

Example

CSS

#wrapper {
  border: 1px solid black;
  width: 250px;
  height: 250px;
}

#masked {
  width: 250px;
  height: 250px;
  background: blue linear-gradient(red, blue);
  mask-image: url(https://mdn.mozillademos.org/files/12676/star.svg);
  mask-repeat: no-repeat;
  mask-position: top right; /* Can be changed in the live sample */
  margin-bottom: 10px;
}

Specifications

Specification Status Comment
CSS Masking Module Level 1
The definition of 'mask-position' in that specification.
Candidate Recommendation Initial definition

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
Basic support
Experimental
Chrome Full support 1
Prefixed
Full support 1
Prefixed
Prefixed Implemented with the vendor prefix: -webkit-
Edge Full support 18Firefox Full support 53IE ? Opera ? Safari Full support 4
Prefixed
Full support 4
Prefixed
Prefixed Implemented with the vendor prefix: -webkit-
WebView Android ? Chrome Android ? Edge Mobile ? Firefox Android Full support 53Opera Android ? Safari iOS ? Samsung Internet Android ?

Legend

Full support  
Full support
Compatibility unknown  
Compatibility unknown
Experimental. Expect behavior to change in the future.
Experimental. Expect behavior to change in the future.
Requires a vendor prefix or different name for use.
Requires a vendor prefix or different name for use.

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このページの貢献者: ddbeck, mfluehr, fscholz, wbamberg, Sebastianz, chrisdavidmills, teoli
最終更新者: ddbeck,